Opening tab

ABSTRACT

An opening tab for an easy open container has a depression in one end of the tab with an opening therein for receiving a rivet on a removable panel of the container. The depression has a convex bottom wall comprised of a thinned outer web and a thickened inner washer. The depression further has a sidewall with an annular corrugation. Additionally, there is an annular reinforcement bead around the top outer periphery of the depression.

United States Patent lnventor John Wlbon Rouse Ramsey, NJ. Appl. No 886,901 Filed Dec. 22, 19 69 Patented Aug. 31, I97] Assignee American Can Company New York, N.Y.

OPENING TAB 12 Claims, 3 Drawing Figs.

US. Cl 220/54 Int. Cl B65d 17/00, 865d 17/20, B65d-1 7/24 Field of Search 220/54,

[56] References Cited UNITED STATES PATENTS 3,527,378 9/1970 Scharfet al..... 220/54 3,534,883 10/1970 Khoury 220/54 Primary Examiner-George T. Hall v w Anornejm-RobertP. Auber, George P. Ziehmer, Leonard Rv Kohan andKenneth H. Murray ABSTRACT: An opening tab for an easy open container has a PATENTED M1831 I97. 3.602.390

INVENTOR. J0/I/V W/L50A/ ROI/SE ATTURNEY OPENING TAB BACKGROUND OF THE INVENTION One of the significant recent developments in the packaging industry has been the trend toward the use of easy-opening containers which do not require the use of separate opening tools such as can openers or can punches. One very important type of such container is the tab-opening can wherein a small pull tab is provided to facilitate detachment of a scored removable panel which is formed in one of the walls of the can.

In this type of can, the removable panel is defined by at least one weakening score which is impressed directly into the metal of the can and may take any suitable shape. Thus, in containers designed to permit the dispensing of easily pourable beverages such as beer or soda, the score is usually shaped to provide an elongated keyhole-shaped opening which permits easy vented flow of the liquid, while in containers designed to contain solid products, the score comprises a tearing line which rims an entire wall of the can to permit complete removal of the wall to provide ready access to the contents.

In all such cans, the opening tab generally takes the form of a rigid lever which is permanently secured to the can wall by a rivet which is formed integral with the removable wall panel and passes through a small opening formed in one end of the tab, the end of the tab opposite its riveted end being formed into a handle which is engageable by a finger of the user, who first lifts the handle portion of the tab upwardly away from the can wall to thereby cause a part of the tab to exert a fulcruming force on the metal on one side of the score or on the score itself to initiate the breaking out of the metal in the weakened score line in an area surrounding the rivet.

In this manner, a lifting leverage is obtained by utilizing the opening tab as a second class lever, but the force heretofore necessary to initiate the breaking out of the weakened scored metal has been relatively high because of the fact that the edge of the tab at the end of the tab opposite the handle end thereof which has functioned as the fulcrum of the tab had to be located at a substantial distance from the rivet in order to provide sufficient strengthening metal in the tab around the rivet to prevent inadvertent breakage and detachment of the tab from the rivet. As a result, the mechanical advantage of the tab has been relatively low.

The present invention has made possible a substantial reduction in the force required to initiate the breakout of the scored area by providing the tab in the area around the rivet opening with a new and improved strengthened wall construction which has the effect of moving the fulcrum of the opening tab much closer to the rivet than has heretofore beenpossible,

thereby increasing the mechanical advantage of the lever and reducing the amount of lifting force necessary to initiate the rupture or breakout of the score.

By the provision of this new and improved strengthened wall construction in the area around the rivet opening of the tab, the present invention further permits reduction in the gauge of tab stock to be used, thus resulting in a substantial reduction in cost of materials. 7

SUMMARY OF THE INVENTION The opening tab involved in the present invention has at one end a handle and at the other end a frustrum-shaped depression with an opening centrally located in the bottom wall of the depression for receiving the rivet on a can wall. The depression in the tab has a new and improved construction, which strengthens the tab and thus allows for the use of smaller gauge tab stock, comprised of a convexly shaped bottom wall having an outer thinned annular web and an inner thickened annular washer therein, a sidewall having an annular corrugation therein and an annular reinforcement bead surrounding the top outer periphery of the depression. Furthermore, the convex shape of the bottom wall allows only the outer peripheral edge thereof to DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an end closure embodying the present invention; 1

FIG. 2 is an enlarged vertical sectional view taken substantially along the line 2-2 of FIG. 1 showing the depression area of the opening tab in securement with a rivet and its associated removable panel.

FIG. 3 is an enlarged vertical sectional view similar to that shown in FIG. 2, but showing the depression area of the opening tab with the rivet and its associated removable panel omitted.

DESCRIPTION OF THE PREFERRED EMBODIMENT As a preferred and exemplary embodiment of the present invention, FIGS. 1 and 2 disclose a circular can end closure 110, preferably formedof a suitable metal such as aluminum, tin plate or steel, formed with a circular central wall 12.

A keyhole-shaped removable panel 14 in the wall 12 is defined by an endless score 16 which is indented directly into the metal of the end closure 10 in a conventional manner. Of course, the removable panel 14 may be given any desired shape, and, further, it may be positioned on any wall of the can, be it a body wall or an end wall. At the inner end 18 of the removable panel 14, the score 16 extends semicircularly around an upwardly extending hollow rivet 20 which is formed integral with the removable panel 14 and may be disposed at the center of the end closure 10, for purposes of symmetry to facilitate handling.

An opening tab, generally designated 22, provided for securement to the removable panel 14 via the rivet 20, has a generally flat body 24 with a handle 26 formed at one end of 'the body 24 and a frustrum-shaped depression, generally designated 28, formed at the other end of the body 24. The handle 26 may be in a ring-shaped form or any other suitable shape. FIG. 3 illustrates the opening tab 22 substantially as it is shown in FIG. 2 except that the tab 22 is shown by itself, without the rivet 20.

The depression 28 has a convexly formed bottom wall 30 defining an opening 32 for receiving the rivet 20. When the tab 22 is secured to the removable panel 14, the rivet 20 fills the opening 32 with the top of the rivet, an enlarged head 34, formed as a consequence of the riveting operation, overlying the metal of the tab 22 around the periphery of opening 32. The rivet20 may, if desired, be of the type disclosed in U.S. Pat. No. 3,191,797.

The convex shape of the bottom wall 30 of the depression 28 is such that only the peripheral edge 33 of the bottom wall 30 contacts the removable panel 14. During the can opening operation, the bottom wall edge portion 35, which is on the side of the rivet 20 opposite from the score 16, acts to exert a fulcruming force on the score 16 to initiate the breaking out of the metal in the score 16 in the area adjacent to and partially surrounding the rivet 20. The convex shape of the bottom wall 30 also assures that, during the can opening operation, the diameter of the opening 32 in the tab 22 will decrease in area when the tab 22 is pulled and will not increase in area to allow the tab 22 to separate from the rivet 20 of the removable panel 1-4. In other words, the upward pull on the tab 22 will tend to tighten the tab stock about the rivet 20, rather than enlarge the opening 32.

The bottom wall 30 of the depression 28 further has an outer thinned annular web 36. The web 36 is formed by coining the metal in this area of the bottom wall 30 to cause a portion of the metal to move radially into the central area of the bottom wall 30. For example, in a bottom wall having a thickness of 0.0l20 inches, the outer annular portion of the bottom wall is coined to a thickness of 0.0l0 inches to form the thinned annular web. After the opening 32 is punched in this central area of the bottom wall 30, the periphery of the opening 32 forms an inner thickened annular washer 38. The thinned annularweb 36, in relation to the thickened annular washer 38, is thereby made flexible to allow flexing of the tab, which may occur in the area of the depression 28 during the can opening operation to occur in the web 36, and not in the periphery of the opening 32, the thickened annular washer 38. in other words, the metal around the opening 32 which forms the thickened washer 38 is stronger than the metal which forms the thinned web 36. Therefore, as a complement to the function performed by the convex bottom wall 30, the web 36 and the washer 38 function to prevent distortion of the opening 32 from occurring during the upward pull on the tab 22 in the can opening operation.

As a further strengthening feature, the sidewall 39 of the depression 28 is annularly corrugated to form an intermediate step 40 to prevent sidewall flexure during the can opening operation.

Additionally, an annular reinforcement bead 42 at least partially surrounds the top outer periphery of the depression 28 so that the remainder of the tab 22 is below the top of the bead 42. Also, the provision of this bead 42 will prevent bending or distortion of the depression 28.

It can easily be seen that the incorporation of all these new structural features into the area of an opening tab where it is riveted to a can wall strengthens the opening tab to such an extent that it allows for the reduction in the gauge of tab stock needed to be used.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof.

I claim: 1. An opening tab for a container having a removable panel in a container wall, comprising: a generally flat body; a handle formed at one end of the body; a frustrum-shaped depression formed at the other end of the body; and a bottom wall convexly formed in the depression having an opening defined therein for reception of a rivet for securement of the tab to the removable panel in the container wall such that only the peripheral edge of said bottom wall contacts said removable panel. 2. An opening tab for a container according to claim 1 further comprising:

an outer thinned annular web formed in the bottom wall of the depression. 3. An opening tab for a container according to claim 1 further comprising:

an inner thickened annular washer formed in the bottom wall of the depression defining said rivet opening therein. 4. An opening tab for a container according to claim 1 further comprising:

an annularly corrugated sidewall formed in the depression. 5. An opening tab for a container according to claim 1 further comprising:

an annular bead formed at least partially around the top outer periphery of the depression. 6. An opening tab for a container according to claim 2 further comprising:

an inner thickened annular washer formed in the bottom wall of the depression defining said rivet opening therein. 7. An opening tab for a container according to claim 2 further comprising:

an annularly corrugated sidewall formed in the depression. 8. An opening tab for a container according to claim 2 further comprising:

an annular bead formed at least partially around the top outer periphery of the depression. 9. An opening tab for a container according to claim 6 further comprising:

an annularly corrugated sidewall formed in the depression. 10. An opening tab for a container according to claim 6 further comprising:

an annular bead formed at least partially around the top outer periphery of the depression.

11. An opening tab for a container according to claim 9 further comprising:

an annular bead formed at least partially around the top outer periphery of the depression.

12. A container component comprising:

a container wall;

a removable panel in said wall defined by a score;

a rivet formed integral with removable panel adjacent to said score;

an opening tab having a generally flat body;

a handle formed at one end of said body;

a frustrum-shaped depression formed at the other end of said body;

a bottom wall convexly formed in the depression having an opening defined therein, said rivet filling said opening and having an expanded head for the securement of said tab to said removable panel, such that only the peripheral edge of said bottom wall contacts said removable panel;

an outer thinned annular web formed in the bottom wall of the depression;

an inner thickened annular washer formed in the bottom wall of the depression defining the opening filled by the rivet and overlapped by the expanded head of the rivet;

an annularly corrugated sidewall formed in the depression;

and

an annular bead formed at least partially around the top outer periphery of the depression. 

1. An opening tab for a container having a removable panel in a container wall, comprising: a generally flat body; a handle formed at one end of the body; a frustrum-shaped depression formed at the other end of the body; and a bottom wall convexly formed in the depression having an opening defined therein for reception of a rivet for securement of the tab to the removable panel in the container wall such that only the peripheral edge of said bottom wall contacts said removable panel.
 2. An opening tab for a container according to claim 1 further comprising: an outer thinned annular web formed in the bottom wall of the depression.
 3. An opening tab for a container according to claim 1 further comprising: an inner thickened annular washer formed in the bottom wall of the depression defining said rivet opening therein.
 4. An opening tab for a container according to claim 1 further comprising: an annularly corrugated sidewall formed in the depression.
 5. An opening tab for a container according to claim 1 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 6. An opening tab for a container according to claim 2 further comprising: an inner thickened annUlar washer formed in the bottom wall of the depression defining said rivet opening therein.
 7. An opening tab for a container according to claim 2 further comprising: an annularly corrugated sidewall formed in the depression.
 8. An opening tab for a container according to claim 2 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 9. An opening tab for a container according to claim 6 further comprising: an annularly corrugated sidewall formed in the depression.
 10. An opening tab for a container according to claim 6 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 11. An opening tab for a container according to claim 9 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 12. A container component comprising: a container wall; a removable panel in said wall defined by a score; a rivet formed integral with removable panel adjacent to said score; an opening tab having a generally flat body; a handle formed at one end of said body; a frustrum-shaped depression formed at the other end of said body; a bottom wall convexly formed in the depression having an opening defined therein, said rivet filling said opening and having an expanded head for the securement of said tab to said removable panel, such that only the peripheral edge of said bottom wall contacts said removable panel; an outer thinned annular web formed in the bottom wall of the depression; an inner thickened annular washer formed in the bottom wall of the depression defining the opening filled by the rivet and overlapped by the expanded head of the rivet; an annularly corrugated sidewall formed in the depression; and an annular bead formed at least partially around the top outer periphery of the depression.
 2. An opening tab for a container according to claim 1 further comprising: an outer thinned annular web formed in the bottom wall of the depression.
 3. An opening tab for a container according to claim 1 further comprising: an inner thickened annular washer formed in the bottom wall of the depression defining said rivet opening therein.
 4. An opening tab for a container according to claim 1 further comprising: an annularly corrugated sidewall formed in the depression.
 5. An opening tab for a container according to claim 1 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 6. An opening tab for a container according to claim 2 further comprising: an inner thickened annUlar washer formed in the bottom wall of the depression defining said rivet opening therein.
 7. An opening tab for a container according to claim 2 further comprising: an annularly corrugated sidewall formed in the depression.
 8. An opening tab for a container according to claim 2 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 9. An opening tab for a container according to claim 6 further comprising: an annularly corrugated sidewall formed in the depression.
 10. An opening tab for a container according to claim 6 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 11. An opening tab for a container according to claim 9 further comprising: an annular bead formed at least partially around the top outer periphery of the depression.
 12. A container component comprising: a container wall; a removable panel in said wall defined by a score; a rivet formed integral with removable panel adjacent to said score; an opening tab having a generally flat body; a handle formed at one end of said body; a frustrum-shaped depression formed at the other end of said body; a bottom wall convexly formed in the depression having an opening defined therein, said rivet filling said opening and having an expanded head for the securement of said tab to said removable panel, such that only the peripheral edge of said bottom wall contacts said removable panel; an outer thinned annular web formed in the bottom wall of the depression; an inner thickened annular washer formed in the bottom wall of the depression defining the opening filled by the rivet and overlapped by the expanded head of the rivet; an annularly corrugated sidewall formed in the depression; and an annular bead formed at least partially around the top outer periphery of the depression. 